Exhaust steam injector



June 1, 1937. R. D. METCALFE ET AL 2,082,295

EXHAUST STEAM INJECTOR Filed Sept. 4, 1936 Patented June 1, 1937 UNITED STATES PATENT OFFICE Metcalfe, Romiley,

England,

assignors to Davies & Metcalfe Limited, Romiley, England,

a British company Application September 4, 1936, Serial No. 99,500 In Great Britain October 5, 1935 1 Claim.

This invention relates to exhaust steam injectors and particularly to what is known as the change over valve, i. e. the shuttle valve which controls the flow of live steam throttled down to a low pressure to the injector when exhaust steam is not available for operating it. The shuttle valve comprises a piston portion and a valve head with seats at its opposite sides, the lower seat preventing the flow of throttled-down live steam to the injector when there is live steam passing to the engine from which the injector obtains its exhaust steam, and the upper seat forming a seal to prevent live steam passing to the connection to the exhaust steam valve control piston of the injector. A check valve acted upon by the pressure of the steam passing from the engine steam chest seats above the piston of the shuttle valve in which position it forces the said shuttle valve on to its lower seating to prevent the passage of the throttleddown live steam to the injector when steam is being supplied to the engine, that is when exhaust steam is available.

The object of the present invention is to provide an improved construction of the change over or control valve which will be more durable and therefore more reliable than the present construction.

The invention consists in a change-over valve for an exhaust injector having its piston portion movable within a ported sleeve which screws into the valve body and which provides at one end a seating for the usual check valve and at its other end a seating for the upper seating of the shuttle valve connected to the piston, such upper seating controlling the flow of throttleddown live steam through the ported sleeve to the piston which opens the exhaust steam inlet valve of the injector.

The accompanying drawing is a sectional view through a change-over valve constructed in accordance with this invention.

The piston it works in a sleeve 1) which screws into the valve body at c and which provides seating surfaces d, e on its opposite end faces, one it for the check valve f and the other e for the upper seating g of the shuttle valve 72 when it is acting to prevent steam passing by way of the ports 1 and passage 7' to the exhaust steam valve control piston of the injector (not shown) so that such valve can close. The piston a is made of considerable axial length with preferably peripheral or circumferential grooves therein and both sleeve b and piston a are made of stainless or rustless steel. When the valve g is clear of the seat e, steam passes from the steam space 70 through the ports 11 in the sleeve 1) to the cylinder containing the piston which opens the exhaust steam control valve. The said ports or holes 2' may serve as a means for turning the sleeve 19 by a suitable tool, so that the sleeve may be easily removed for renewal when worn.

Live steam is admitted to the valve fitting by the pipe m and is wire drawn by the nozzle n to give low pressure steam to work the injector when exhaust steam is not available. When the lower seating o of the shuttle valve is open, such low pressure steam passes to the pipe p and so to the injector (not shown).

Exhaust steam enters the chamber q through the pipe 1'. When the engine is not working the pressure in the chamber q is relieved. Water formed by condensation of the steam is removed by the drip valve s. The non-return valve t prevents formation of a vacuum in the chamber q by admitting air thereto.

The valve h is lifted when the chamber q is clear of exhaust steam pressure by the action of the pressure of throttled-down live steam upon the under side of the piston a.

What we claim is:

A change-over valve for an exhaust steam injector having its piston portion movable within a ported sleeve which screws into the valve body and which provides at one end a seating for the usual check valve and at its other end a seating for the upper seating of the shuttle valve connected to the piston, such upper seating controlling the flow of throttled-down live steam through the ported sleeve to the piston which opens the exhaust steam inlet valve of the injector.

RICHARD DAVID METCALFE. JAMES CROXON METCALFE. 

